\begin{tikzpicture}
	\pgfmathsetmacro{\R}{2.5}
	\tkzDefPoints{0/0/O, \R/0/G}
	\tkzDefPoint(30:\R){K}
	\tkzDefPoint(60:\R){H}
	\tkzDrawSegments(O,G  O,K  O,H)
	\tkzMarkAngle[size=0.5](G,O,H)
	\tkzLabelPoints[left](O)
	\tkzLabelPoints[below](G)
	\tkzLabelPoints[right](H, K)
\end{tikzpicture}

